The Cannabis Life Cycle

Cannabis is ‘genus’ or family of 3 separate species of plants. Two of these, Cannabis Indica and Cannabis Sativa are well known. Cannabis Ruderalis is the 3rd family member, and has been the subject of intense research in the last few years as Autoflowering cannabis has become a mainstream choice of home growers.

Cannabis is dioecious, meaning it can male or female. For cannabis growers the female plant is of main interest and male plants are discarded. The female plant grows the buds which we all love whether for recreational and/or medical reasons. Male cannabis plants are of less interest to cannabis home growers, they are generally thrown away to prevent their pollen from producing seeds in the buds.

Above. The tap root emerges from a seed and life begins

In the 1990’s Henk van Dalen of Dutch Passion discovered how to feminize cannabis seeds. Feminized cannabis seeds give rise to 95%+ female plants. Today feminized seeds account for almost all cannabis seeds sold. Non-feminized (‘regular’) seed produces males and female plants in roughly equal numbers, they are often grown by old-school growers or those experimenting with their own breeding projects.

There are two ways to grow a cannabis plant, from seed or from a cutting. Cuttings (‘clones’) of traditional photoperiod cannabis plants allow the grower to grow a genetically identical version of the parent. Seeds are more convenient for many people, they can be stored for many years until needed and will produce larger plants than those grown from cuttings though they will not be genetically identical to the parent in the way a cutting is.

Above, a young cannabis seedling a few days into life

Germination

There are 3 key stages in the cannabis life cycle. Assuming that you are growing from seed the first stage is germination. During germination the seed absorbs water allowing it to swell and the first sign of life, a root, emerges. This is often called the tap root and it will grow quickly into soil, rock wool or any other medium. Cuttings can grow their own roots simply by dipping into hormone-rooting powder. As a young seedling the cannabis plant is at its most vulnerable, it can be damaged (and often is) if the grower attempts to feed strong nutrients. Water or extremely dilute feed solution is sufficient. Many soil growers prefer to use organic nutrients prepared using entirely natural methods, however these can block the pipes and nozzles in hydroponic systems forcing many hydroponic growers to use non-organic nutrients. But non-organic nutrients will still do a great job of growing the plant. There are many well known nutrient brands available to the home grower such as Top Crop, Bio Nova, Bio Tabs, BAC, Aptus, Plagron, BioBizz, Canna, Advanced Nutrients etc. They provide nutrients optimised for the different grow methods, and their websites provide more precise details on what their nutrients do and how to use them.

Above. A fully mature Think Different grown in DWC under a 600W HPS light by Bambud

The cannabis root system is responsible for the absorption of minerals and nutrients into the plant, in optimum conditions the root system can be large. Roots need oxygen and nutrients to develop and remain healthy. The two most common ways people accidentally restrict root development is through overwatering the plants (in soil) or overfeeding which ‘burns’ them. Cannabis roots can grow well in water-based hydroponic systems so long as they are also supplied with plenty of oxygen, otherwise the roots will rot. Often nutrient companies will prepare special root nutrients which will allow healthier root development. Soil growers may wish to add some Mycorrhiza beneficial fungi to their soil to allow better root growth. In Hydroponic systems growers often use an additive such as Rhizotonic which will also aid root growth. Always read the manufacturers instructions carefully and avoid the beginners temptation to overfeed your plants, this will damage the roots (‘Nutrient burn’) and slow down plant growth.

Organic soil growers may also choose to add other nutrients in small amounts to their soil such as worm castings, bat guano, seaweed extracts etc. New growers can simplify matters dramatically by buying a pre-prepared soil mix (from internet or grow store) which will contain the essential ingredients. The best advice for new growers is to keep it simple, not all the additives are essential unless you are an experienced grower that knows exactly how to use them. Remember in the wild cannabis grows very happily in ordinary soil.

Above, Frisian Dew grown outdoors in central Europe. With unrestricted root space the best cannabis varieties can reach 3m+ tall and produce several kilograms of bud

Vegative growth.

Growth in photoperiod cannabis varieties is manipulated using the light. For indoor growers this means the plant will grow in veg mode with a system of e.g. 18 hours light and 6 hours darkness. The plant will grow leaves, roots and branches but no buds. During this stage of its life the plant will often respond well to nitrogen-rich fertilisers.

Flowering

When the light cycle is switched to 12 hours light/12 hours darkness the plant responds with some biochemical and hormonal changes which causes the plant to start preparing to flower. Growers often call this putting the plant ‘into bloom’. The plant will start stretching upwards and develop light emerald-green foliage near the eventual bloom sites. The plant will also start requiring less Nitrogen-based feed and increasing amounts of Phosphorus and Potassium. Autoflowering varieties do not need daylight hours reducing to 12 hours per day, instead they start to bloom ‘automatically’ after around 25 days and continue to bloom regardless of light cycle until they are harvested around day 75. In general terms, more light means more buds. Dutch Passions preferred artificial light source is LED which is more efficient and less energy demanding than HPS.

Above, a selection of cannabis plants grown under LED by Tang at different stages of bloom

Nutrients often come with an ’N:P:K’ ratio on the side. This indicates the comparative amounts of Nitrogen to Phosphorus to Potassium. Nutrients optimised for vegetive growth will often have a higher amount of Nitrogen (e.g. NPK 1:1:1) compared to nutrients designed for bloom (e.g. NPK 1:2:2)

Small pre-flowers will appear on the plants which indicate sex. The female plants will often show a couple of small white hairs (pistils) emerging from a nodule between stem and branch. This indicates the start of flowering. The length of flowering will depend on the variety, but it is usually around 8-9 weeks. At this stage the cannabis plant puts all its energy into laying down the thick layers of bloom and resin which we all love. The ultimate goal of the plant in nature is to be pollinated, however the home-grower will remove any male plants to prevent the buds being filled with seeds. Everyone prefers sinsemilla, which means seed-free cannabis.

The development of the plant as a seedling, in veg growth and in bloom is perhaps faster in hydroponic systems than soil. On the other hand, hydroponics can be hard to master. Whichever system you choose to grow cannabis the end result is the same - plenty of good quality home grown marijuana.

An epic AutoMazar grown in DWC (deep water culture) under HPS, Plasma and LED

As the cannabis plant continues to bloom the appearance changes dramatically. The best cannabis genetics allow the plant to be covered with heavy blooms that can cause the branches to bow down due to their own weight. The plant will also start to produce a sticky coating of resin, the resin is rich in cannabinoids that produce the desired medical/recreational benefits.

Harvest

After a couple of months of producing blooms the plant is near harvest time. The hairs (pistils) which emerge from the blooms start to change from white to orange and the resin glands (‘trichomes’) start to change from a transparent appearance cloudy and eventually amber. Many growers have their own preferred harvest times for specific varieties. If harvested with clear trichomes a variety may have a strong cerebral and psychedelic effect. But if the same variety is left for a further 2-3 weeks the pistils will be mostly orange and the trichomes mostly amber, this can give a heavier effect with a more noticeable body-stone and probably a bigger harvest too. Much depends on the personal preferences of the individual grower, there is no ‘right’ or ‘wrong’ way to grow or harvest your cannabis, find a way that works for you. And remember there is plenty of detailed cannabis grow/nutrition information online or in books.

Cannabis is easy to grow, it is called ‘weed’ for a good reason and can be grown in many different ways. Growing in a specialist pre-prepared soil is probably the easiest way to start growing cannabis. If you use a large enough soil container, 20 litres+, you will just have to plant the seed and add water for the first month or two and perhaps add some diluted bloom feed for the last month. Growing in hydroponic systems may require more experience and equipment than the beginner can manage. But after just a few grows your experience and growing confidence will increase. Everyday plenty of new cannabis growers plant their first seed and many of them will go on to grow the best pot they have ever smoked.

Choose your seeds from a seed bank you trust, seeds are one area of your grow where you don’t want to compromise. And good luck; once you have grown your own cannabis you will not want to buy it again. Not only that, but growing your cannabis is enjoyable, rewarding and highly satisfying.

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Recent comments (2)

On 08 -05-2016 at 11:24 u Hike Singh wrote:I would like to have a batch of your finest seeds.

On 10 -02-2017 at 21:57 u Ronja wrote: This article was excellent and very informative. I create my own soil and add my nutrients as the girls require not just adding nutrients because you think they need them. I pay attention to the soil and use the finger feel method as it has worked with flawless results in the past. As I have grown for a little time now I have gained experience and confidence as the article says and I agree I grow some of the best Medical I have been told by people who have smoked. Thank you and Spot On!

Seed type

Dutch Passion advise their customers to reassure themselves of local applicable laws and regulations before germination. Dutch Passion cannot be held responsible for the actions of those who act against laws and regulations that apply in their locality. Cannabis seeds should be kept as collectible souvenirs by anyone in an area where cultivation of cannabis is not legal.